Manuel Pellegrini says he will field a weakened Manchester City for the FA Cup fifth round tie at Chelsea if the Football Association choose to stage it on 21 February, three days before the Champions League last-16 trip to Dynamo Kyiv.

The City manager pointed to Chelsea’s first leg at Paris Saint-Germain, which is on 16 February, the previous Tuesday, making the point that if the FA Cup tie were on the Saturday each club would have three days’ break either side of it.

City remain in four competitions; they are also in this month’s Capital One Cup final and are second in the Premier League, three points behind Leicester City, who visit the Etihad Stadium on Saturday. If the manager were to select a side with the Kyiv match in mind it would lessen City’s chances of defeating Chelsea and so put in threat their chances of an unprecedented quadruple.

Pellegrini said: “I’m very worried for a lot of things. First and foremost, if we have to play that game on that Sunday, we will not play with our [full-strength] team, we will play with a young team. We have to travel to Ukraine on Monday, so I don’t see any reason why we can’t play on the Saturday. Chelsea play their Champions League game on the Tuesday before. So if we have to play on the Sunday, we will have to see which players will have to play.

“I don’t want to analyse why, but I think if we have to play against Chelsea four days before, we should play on the Saturday. If we play on the Sunday, we have to put Manchester City’s interests first. For me, I must do what I feel is best for the club, to play with the strongest team we can in the Champions League. Also, if we continue in the FA Cup, we will have to postpone two Premier League games, and there is no option to play those games in midweek.”

City are without Kevin De Bruyne, Wilfried Bony, Jesús Navas, Samir Nasri, Eliaquim Mangala and Vincent Kompany for Saturday’s visit of Leicester.

Pellegrini said: “Kompany and Mangala both started working partially with the squad – unfortunately Mangala has another injury and he’ll be another couple of weeks.

“I hope after another week, Vincent will be back working with the squad fully. We know exactly what happened with the injury to Vincent now. The risk for the future is exactly the same as it is with every player. It’s important now for Vincent to start playing again as we have just 14 senior players. That’s not so many for so many games.

“Navas has a muscle injury in his hamstring. He’ll be out for a minimum of three weeks. We didn’t expect Bony to be out for so long but I hope next Monday we will see a full medical report. He’s improving a lot but it’s an inflammation of the bone which is bringing him a lot of pain. We’ll see if he can start working with the squad next week.”

Pellegrini also tried to close down anymore questions regarding Pep Guardiola’s replacement of him as head coach on 1 July. “It’s important to talk about this season and not the next one. I’m not talking about those things – we just talk about the present. Just ask me about the team and the game,” he said. “The players must always think about the next game as it’s the only way to be successful.

“With or without the news, things in football change so quickly. It’s the same at every club – the players must know that they must win the next game and that’s why we’re just thinking about Leicester.

“Very happy with the support from fans – not just because they knew what happens next season but for the whole two and a half seasons but because we play good football and challenge for titles, always trying to be a scoring team.”